HIV continues to spread around the world and new infections in Asia are one of the most important areas for prevention among drug using populations. There is strong and consistent evidence from several countries that while injection drug users (IDU) continue to be a source of new infections, treatment of opiae addiction is an effective prevention measure against further spread. Among those IDU already infected, substance abuse treatment can improve access and adherence to HAART therapy and promote sustained viral suppression. The proposed project will take place at the Go Vap HIV clinic in Ho Chi Minh City (HCMC), Vietnam. Vietnam is an original PEPFAR country and has experienced a major HIV epidemic that has been propelled by injection drug use. In HCMC, it is now estimated that 51.8% of injection drug users (IDU) are HIV positive. While the country has begun the scale up of methadone maintenance treatment (MMT), coverage remains inadequate and the rate of expansion of new treatment programs clearly needs to be accelerated in order to have meaningful impact on the epidemic. For heroin (and other opiate) dependent individuals, methadone maintenance has limited availability and there are currently no buprenorphine/naloxone (Suboxone) treatment programs in Vietnam. This newer medication has the possibility of making treatment available to more patients because of the efficiency of three times per week dosing and, given the high prevalence of HIV among drug users in HCMC, fewer interactions with antiretroviral medications. These factors motivated the Provincial AIDS Committee of HCMC to seek support in expanding drug treatment to both HIV positive and negative IDUs as a model prevention program. These discussions have led to the current proposal that will begin with the implementation of a comprehensive training program on addiction and medication assisted treatment (MAT). Following this training the program will introduce MMT at the Go Vap clinic. In the second year, daily methadone will continue to be available and selected patients will be given the opportunity to be treated with Suboxone progressing from daily to thrice weekly observed treatment. All participants also will be engaged in behavioral drug and risk counseling. During the course of the project we project enrolling 300 IDUs (150 HIV + and 150 HIV-) into MAT treatment program co-located with the Go VAP clinic. We are not proposing a comparison between methadone and Suboxone. Both are safe and effective medications. We will demonstrate feasibility and evaluate participant, clinic, and community factors that promote or inhibit program implementation. We will measure costs and identify factors that are associated with treatment success for each medication and for positive and negative participants. Importantly, the program is being implemented in partnership with the Provincial AIDS Committee of HCMC and will contribute to their goal of expanding access to both drug abuse and HIV treatment.